Featured Research - Quail Ridge Reserve

Prasant Mohapatra,
Department of Computer Science, UC Davis

Wireless Mesh Networks

Imagine a natural disaster scenario – tsunami, earthquake, or flood – that knocks out electricity and telephone service. Coordinated rescue and relief efforts are essential to crisis management. Such efforts require a flexible communications system, and wireless Mesh Networks (WMNs) may be the best solution to overcome the physical and temporal constraints of the situation. WMNs are composed of wirelessly interconnected access points, called mesh routers, that provision access to the Internet and interconnectivity between the mesh clients. Due to their low cost, low power consumption, and tetherless capabilities, WMNs can be quickly and strategically deployed to support voice over Internet, video conferencing, and Web access, providing the communication infrastructure necessary for dealing with these emergency scenarios.

In addition to disaster situations, WMNs have seen increased deployments in the areas of broadband home networking and enterprise networking. They are also being deployed at the community and municipal level both for extended service provider coverage to end users, and in areas lacking wired infrastructure.

Researchers in the Department of Computer Science are working to perfect WMNs for efficient, wide-scale deployment by improving efficient spectrum utilization, robustness to interference and fading, reduction of contention and interferences, efficient routing, fault management, security enforcement, quality of service, and high throughput. The testbed for this work is QuRiNet – a unique, broad scale outdoor wireless mesh network at the Quail Ridge Reserve.

The largest noise-free wildland network in the world, QuRiNet is powered exclusively by solar cells, making it an ideal model for use in developing countries. The wildland setting provides challenging terrain for the network but, more importantly, the remote location provides an environment free from electronic interference. Because the characteristics and nature of wireless networks have inherent variation, accurate evaluations can be quantified only through actual experimentation. Almost all other mesh testbeds suffer from external signal interferences due to nearby wireless networks. Although these interference-prone testbeds mirror real-world scenarios, it is often difficult to untangle which effects are caused by which factors - new protocols or interference from nearby networks? QuRiNet complements other testbeds by allowing researchers from all over the world to compare results between “noisy” and interference-free systems.

A number of environmental monitoring applications are now using the WMN as a communication backbone. Several router locations are equipped with weather stations that are accessed remotely by class groups and by researchers interested in timing their data-collection visits to precise phenological events. High-quality microphones are installed at nodes near bodies of water to monitor amphibian vocalizations. The network also transmits photos and videos from bait stands and from modified pitfall traps where the “pit” has been replaced with motion-detector cameras. Soon, state-of-the-art receivers will be overlaid to form the world’s second fine-scaled automated animal-tracking system.